<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        
        function getSum(m, n) {
            let sum = 0
            for (let i = m; i <= n; i++) {
                sum += i
            }
            return sum
        }
        let m = +prompt(`请输入第一个数`)
        let n = +prompt(`请输入第二个数`)
        let result = getSum(m, n)
        document.write(`累加和是${result}`)
    </script>
</body>

</html>